Refrigeration



Se t. @1932. EARNSHAW 1,876,212

REFRIGERATION Filed March 25, 1951 ,1 0L. I I

I Woman 5 WITNESSES Patented Sept. 6, 1932 UNITED STATES PATENT OFFICE.

REFRIGERATION Application filed March 25, 1931. Serial No. 525,145.

This invention relates to refrigeration and more particularly to mechanical systems in which condensation and evaporation of a volatile media takes place during the refrigcrating cycle,

and lighter gases involved has been effected by washing, or absorption of the refrigerant gas by some medium, from which it later was driven out.

Fundamentally, the principle involved in my invention is that two gases of differing molecular weights may be efficently separated by the use of filter screens to utilize their difference in diflusion activity, according to Grahams law, in conjunction with centrifugal action to reenforce the separation by diffusion and also to carry away the diffused light gas, while at the same time the undiffused heavy gas is removed from the area of diffusion. By multistage repetition of this as provided for, practically any degree of separation may be arrived at, with the expenditure of relatively little power and without the intervention of additional agents. Using the system of partial pressures in an hermetically sealed circuit, the gases, once separated after leaving the evaporator, are returned to it, the refrigerant as a liquid after cooling and condensation, the light gas being unchanged.

The primary object of my invention is to provide a novel-condenser-separator-evaporator refrigerating system wherein the customary refrigerant and inert gases under pressure, after evaporation of the refrigerant gas into the inert gas in the evaporator, are separated by multiple-diffusion reinforced or aided by centrifugal action.

Another object of this invention is to take advantage of the difference in diffusion activity of the refrigerant and inert gases, as well as their difference in molecular weight, incident to progressive multiple-diffusion through a porous medium under centrifugal action, to effect proper balancing of the fiow of the respective separated gases.

A further object of my invention is to provide an apparatus adapted to the above stated objeetswhich is of simple construction, de-

and separation of the heavier pendable in operation, and not liable to get out of order under continuous use.

With these general objects in view, and others that will hereinafter appear, this invention essentially involves evaporating the refrigerating fluid under pressure in an atmosphere of a relatively inert non-condensible gas, separating the two gases under pressure from the resultant mixture by filteringcentrifugal action, and condensing the rego frigerating gas for re-evaporation in the recovered inert gas, with a novel means adapted thereto.

The various features of novelty whereby the invention is characterized will, hereinas after, be pointed out with particularity in the claims; but for a full understanding thereof, reference is to be had to the following detailed explanation of the accompanying drawing, which is a vertical section through a refrigerating apparatus adapted to the present improvements.

Referring to the illustration, which shows one practical embodiment of my invention by way of example only, the numeral 10 com- 76 prehensively designates an evaporator, while 11 and 12, respectively, and similarly, indicate a gas separator and a condensing coil.

The separator 11 is enclosed within a hermetically sealed housing 13 which, in the 80 present instance,'is sunk part way into a recess 14 in the top 15 of a refrigerator casing (not shown) with the hermetically connected coil 12 superimposed upon it; and the evaporator 10 disposed beneath it within said refrigerator casing. The evaporator 10 may be of the usual horizontal U-shapcd crosssectional configuration to afford an interval or space within it for the accommodation of ice pans or trays 16. The separator 11, it will be noted, has the form of a horizontal rotor that tapers from the center towards its periphery, and it is secured to the tubular vertical shaft v17 of an electric motor 18, whereby it is driven at high speed; said motor being enclosed by an upward axial offset 19, of the housing 13, within the confines of the condenser coil 12. The rotor 11 operates as a centrifugal filter to separate the heavier refrigerant gas from the lighter inert gas mixed therewith in the process of evaporation. The rotor 11 is of composite construction, with a hollow spool-like hub 20 circumferentially flanged at the opposite ends 21, and a concentric hollow ring 22, said hub and ring being joined by complementarily dished disk members 23 made from perforated sheet metal, as well as by a rigidly connected central diaphragm 24, likewise of perforated sheet metal. symmetrically arranged between the outer disks 23 and the central diaphargm 24, are diaphragms 25 fine granular material, conventionally indicated at 27 The mixed gases enter the cen tral hollow 28 of the hub member 20 of the rotor 11 from the lower portion of the tubular shaft 17 through ports 29, and from said hollow pass into the packed central part of said rotor by way of apertures 30, in the circumferential wall of the hub member, immediately to opposite sides of the perforated diaphragm 24; the lighter inert gas finally escaping through the perforations in the outer disk members23 of the'separator 11; while the centrifugally influenced heavier refrigerant gas enters the filler packed peripheral ring 22 of the rotor 11 by way of perforations 31. The escaping lighter inert gas is collected within a sealed chamber 32 surrounding the rotor 11, while the upper and lower portions of the said chamber are afiorded communication by way of longitudinal tubes 33 through the hub member 20. The heavier refrigerant gas is conducted from the filler packed ring 22 of the'rotor 11 by curved tubes 34 and collected in a sealed compartment 35 above the chamber'32; said compartment 35 being isolated from the evaporator 10 by a plug 36 secured in the tubular shaft 17 The mixed gases are lifted from the evaporator 10 by suction action of the rotor 11, through a tube 37 which connects into the axial hollow 38 of a lower bearing member 39 for the shaft 17. This bearing member 39 is conveniently sustained in a reduced downward axial extension 40 of the separator housing 13 by a surrounding flange 41. An upward neck portion 42 of the evaporator 10 surrounds the top of the tube 37 and telescopes with the downward extension 40, and is conveniently welded thereto at43, to insure a sealed juncture. With accumulation of emma pressure within the chamber 32 of the rotor 11, the lighter inert gas is forced from the said chamber through a short by-pass tube 44, in the lower portion of the rotor shaft 17, into a cavity 45 surrounding said shaft within the lower bearing 39. From the cavity 45 the lighter gas is conducted down into the evaporator 10 through a pipe 46, the latter having interposed in it a valve 47 which is regulatable to control the gas flow.

The heavier refrigerant gas is forced from the chamber 35 of the rotor 11, likewise by pressure of accumulation, into the upper portion of the tubular shaft 17 by way of ports 48, andthence into the hollow of the top shaft bearing, indicated at 49, via which it enters the condenser coil 12. Incorporated with the juncture fitting at 50 is a regulatable valve 51 whereby the flow of the refriglerant gas may be controlled. The discharge or lower portion 12 of the condenser coil 12 enters the top of the separator casing 13 and connects with another cavity 52 in the lower shaft bearing 39, from whence the condensed refrigerant is conducted, by way of a pipe 53 which has its lower end discharging laterally into the evaporator 10. Within the neck 42 0f the evaporator 10, the pipe 53 is formed with a downward retroversion 54 which is designed to serve as a liquid trap wherefrom any 'uncondensed refrigerant gas, carried along with the liquid may, ordinarily escape through a small top aperture 55, and thence enter the pipe 17, by way of a small hole '17, for circulation through the separator 11, as aforesaid. There are also additional pin restricted apertures 56, provided at difierent levels down the trap 54 through which the uncondensed gas may by-pass more rapidly, as later on explained.

In operation and assuming the method of refrigeration by partial pressures, or the evaporation of a liquid into a gas under pressure, is understood, it will be readily seen that the mixed gas is drawn from the evaporator 10 through tube 37 and hollow shaft 17 to the separator 11; and distributes to each side of the central diaphragm 24. The space between the filter disks 25, 26 being filled with a fairly hard granular substance allows free passage of the inert gas, but it will'carry said gas at the speed of the centrifuge or separator 11, without formation of disturbing currents. Incidentally the perforated metal side wall 23 strengthens the filter 26 and prevents its distortion. The mixed gas entering between the filter plates 25, 26 tends to be driven towards the circumference by centrifugal force of rotation but is retarded by a resistance, later explained. As a result of this resistance a pressure is built up between the filters 25, 26 which forces the gas to pass through them by diffusion according to the degree of internal pressure. The light inert gas diffuses man; t imesm'o're readfrigerant gas travels by way of 22, 34, 35,

17 and condenser coil 12, to said evaporator. The necessary resistance to the flow of the gases through the separator 11 and the balancing of their rates of flow may be effected by regulation of the valves51 and 47; or by the proper proportioning of the parts 32, 34, 35 in regard to shape and Size, with reference to the amount of rotational speed they will impart to the contained gas. In the latter connection it is evident that the balance of centrifugal force tending to accelerate the flow of both gases from, or through, the separator 11 is dependent upon the ratio of the rotational speed of the gases, at the point of final escape, to the speed of the gases in their respective conduits.

To take care of the varying amounts of refrigerant in the mixed gas during the progressive stages of the cycle of opera-tlons, the trap 54 is used. It is likely that ,a complete separation of the gases Will not be desired, so that some uncondensed gas can by-pass the trap 54 through the restricted opening 55. If during the later part of the cycle the quantity of light inert gas admixture increases at this point, it Will be unable to pass through 55 as readily; whereupon an increase in pressure will take place, which by lowering the liquid level will open the successive ports 56. This increased pressure will back-up around to ring 22 and slow down the passage of the heavy refrigerant gas, thereby decreasing the amount of light inert gas admixture.

Attention is here directed to the provision of the apertures 55, 56 with suitable means whereby their area can be varied so that only a predetermined discharge of uncondensed gas may take place at a given pressure. In this manner a degree of automatic control over the purity of therefrigerant gas is ensurcd, since the greater the back pressure the longer said gas remains under action of the separator 11 and, consequently, the purer it will be.

Both the light and heavy gas return pipes 46, 12 can be so constructed that said gases may give up some or all of the heat picked up by them, after enterin the separatorvll, to the mixed gas leaving the evaporator 10.

In case it may be desirable to circulate oil or other liquid, a wick filled tube, or it may be a capillary tube, as indicated at 57, is provided to draw such other'liquid, indicated at 57 from the bottom of the evaporator 10, to the open end 58 of the exhaust tube 37 in case said liquid is heavier than the refrigerant. If the liquid 57 is lighter, it will float on the refrigerant indicated at 10 and be carried as a spray in the mixed gases; while any excess of such liquid will return with the returning gases.

From the foregoing it is-thought that my invention will be understood, but it is to be remarked that the particular combination involved is an improvement overcentrifugal or diffusion separation alone; as the effect of centrifugal action is increased by filtering out the light inert gas leaving most of the heavy refrigerant gas behind. Furthermore, the

known objections of the diffusion methods are overcome, since the diffused gas is removed automatically and not permitted to accumulate; the heavy refrigerant gas is not allowedto remain and increase its ratio in the undiffused gas; While the centrifugal action of the separator ll'tends to prevent the diffusion of heavy refrigerant gas by holding it to a definite course or path.

Finally, a refrigerating apparatus in accordance with my improvements is simple to construct, having little about itliable to get out of order in operation. No heat is added whether from the friction of a compressor or for the distillation of an absorption medium; the efficiency is but little lowered incident to a rise in surrounding temperature, since the internal ressure that causes condensation of the re rigerant gas remains constant; While my invention ensures a more economical apparatus due to reduction of friction and less power consumption.

It is to be understood that I do not limit myself to the precise details of construction and arrangement hereinshown and described. since it is obviously possible to design and proportion the centrifugal diffusion filter and the gas flow passages so that any desired differential pressures may be predetermined for the two gases to compensate for different relative allocation of the evaporator and the condenser.

Having thus described my invention, I

, refrigerant gas for re-evaporation in the recovered inert gas.

3. The method of-fefrigeration which consists in evaporating refrigerant fluid in an atmosphere of relatively inert non-condensible gas under pressure, bringing about separation of the two gases in the resultant mixture by taking advantage of their diflerences in molecular weight under centrifugal-diffusion, and condensing'the refrigerant gas for re-evaporation in the recovered inert gas.

4. The method of refri eration which consists in evaporating refrigerant fluid in an atmosphere of relatively-inert non-condensible gas under pressure, bringing about separation of the two gases in the resultant mixture by taking advantage of their differences in molecular Weight and diffusive-activity aidedby centrifugal force, and condensing the refrigerant gas for re-evaporation in the I recovered inert gas.

5. The method of refrigeration which consists in evaporating refrigerant fluid in an atmosphere of relatively-inert non-condensible gas under pressure, effecting separation of the two gases in the resultant mixture by centrifugal progressive diffusion, and condensing the refrigerant gas for re-evaporation in the recovered inert gas.

6. The method of refrigeration which con sists in evaporating refrigerant fluid in an atmosphere of relatively-inert non-condensible gas under pressure, effecting separation of the two gases in the resultantmixture by combined filtering-centrifugal action, effecting maintenance of a proper balance of flow between the separated gases, and condensing the refrigerant gas for re-evaporation in the recovered inert as.

7. The metho of refrigeration which consists in evaporating refrigerant fluid in an atmosphere of relatively-inert non-condensible gas under pressure, efl'ecting separation of the two gases in the resultant mixture by combined filtering-centrifugal action to take advantage of their difference in diflusion activity, and condensing the refrigerant gas for re-evaporation in the recovered inert gas.

8. The method of refrigeration which consists in evaporating refrigerant fluid in an atmosphere of relatively-inert non-condensible gas under pressure, separating the two gases in the resultant mixture by combined filtering-centrifugal action to take advantage of their difference in diffusion activity and molecular weight in effecting a proper bal-' ance of flow betweenthe separated gases, and condensing the refrigerant gas for re-evaporation in the recovered inert gas.

9. The method of refrigeration which consists in evaporating refrigerant fluid in an atmosphere of relatively-inert non-condensible gas under pressure, utilizing the difference in diffusion activity and molecular weight of the respective gases incident to sepaevaaie aration in eflecting a balance of flow between the separated gases, and condensing the sepbined filtering-centri ugal action, and condensing the separated refrigerant fluid at substantially the above pressure for subsequent re-evaporation in the recovered inert as.- g 12. The method of refrigeration which consists in evaporating a refrigerant fluid into an inert gas under pressure, separating the resultant mixture by combined filteringcentrifugal action, automatically balancing the flow of the separated gases, condensing the separated refrigerant gas at substantially the above pressure for subsequent reevaporation in the recovered inert gas, and

further extracting heat from the condensed returning fluid and gas by absorption into the relatively colder mixture.

13. In refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, evaporator means wherein the condensed refrigerant is gasified in an atmosphere of the inert gas andmixed with the latter, a progressive-diffusion-filter receiving the mixed gases and operative to separate the refrigerant gas from the inert gas, means for liquefying the refrigerant gas, and means for separately returning the liquefied refrigerant and filtered inert gas to the evaporator means.

14. In refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, evaporator means wherein the condensed refrigerant 1s gasified in an atmosphere of the lnert gas and mixed with the latter, a multi-stage diffusion-filter receiving the mixed gases and operative to separate a refrigerant gas condensible at: ordinary temperatures and an inert gas under pressure, evaporator means wherein the condensed refrigerant is gasified in an atmosphere of the inert gas and mixed with the latter, a rotary diffusion-filter receiving the mixed gases and operative to progressively-separate the refrigerant gas from the inert gas, means for liquefying the refrigerant gas, means for separately conducting the liquefied refrigerant and filtered inert gas from the separator to the evaporator without further substantial admixture, and means controlling circulation of a small quantity of other liquid requisite in operation.

16. In refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, evaporator means wherein the condensed refrigerant is gasified in an atmosphere of the inert gas and mixed with the latter, a multi-stage rotary diffusion-filter receiving the mixed gases and operativeto progressively separate the refrigerant gas from the inert gas, means for liquefying the refrigerant gas, means for separately conducting the liquefied refrigerant and filtered inert gas from the sep arator to the evaporator without further substantial admixture, means accommodating circulation of a small quantity of lubricant requisite in operation, and means for extracting heat from the returning liquidand gas by absorption into the colder mlxed gases.

17 In refrigerating apparatus employing a refrigerant gas condensible at ordlnary temperatures and an inert gas under pressure, an evaporator wherein the condensed refrlgerant 1s gaslfied in an atmosphere of the inert gas and mixed with the latter, a.

rotary diffusion-filter receiving the mixed gases and operative to progressively separate the refrigerant gas from the inert gas, a condenser for the refrigerant gas, means for separately returning the refrigerant and filtered inert. gas to the evaporator, and means balancing the flow of the separated refrigerant and inert gases to control the degree of separation of the two gases.

18. In refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, an evaporator wherein the condensed refrigerant is gasified in an atmosphere of the inert gas and mixed with the latter, arotary diffusion-filter receiving the mixed gases and operative to progressively separate the refrigerant gas from the inert gas, a

condenser for the refrigerant gas, means for.

separately returning the refrigerant and filtered inert gas to the evaporator, a hermetically sealed casing housing the diffusion filter and suitable rotating means, and means automatically balancing the flow of the refrigerant and inert gases returning to the evaporator.

19. In refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, an evaporator wherein the condensed refrigerant is gasified in an atmosphere of the evaporator, a hermetically sealed casing housing the difiusion filter and suitable rotating means, and means automatically balancing the flow of the refrigerant and inert gases returning to the evaporator.

20. In a refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, an evaporator wherein the condenser refrigerant is gasified in an atmosphere of the inert gas and mixed with the latter, a rotary diffusion-filter receiving the mixed gases and operative to progressively separate the refrigerant gas from the inert gas, a hermetically sealed casing housing said filter with suitable rotating means and having a gas tight connection to the evaporator, an integrally connected condenser for the refrigerant gas, means for returning the liquefied refrigerant to the evaporator including a trap accommodating escape of any uncondensed refrigerant gas, and separate means for returning the filtered inert gas to the evaporator.

21. In a refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, an evaporator wherein the condensed refrigerant is gasified in an atmosphere of the inertgas and mixed with the latter, a rotary diffusion-filter receiving the mixed gases and operative to progressively separate the refrigerant gas from the inert gas a hermetically sealed casing housing said filter with suitable rotating means and having a gas tight connection totheevaporator, an integrally. connected condenser for the refrigerant gas, means for returning the liquefied refrigerant to the evaporator including a trap with an outlet for normal escape of any uncondensed refrigerant gas and a plurality of other controllable outlets accommodating additional escape under increased pressure of such gas as the admixture of inert gas increases, and separate means for returning the filtered inert gas to the evaporator.

22. In a refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, an evaporator wherein the condensed refrigerant is gasified in an atmosphere of the inert gas and mixed with the latter, a rotary multi-stage diffusion-filter receiving refrigerant to the evaporator including a trap with a controlled outlet for normal escape of any uncondensed refrigerant gas and a plurality of other controllable outlets accommodating additional escape under 'increased pressure of such gas as the admixture of inert gas increases, and conduit means including an interposed regulatable valve for returning the filtered inert gas to the evaporator, both the trap and valve being housed in the sealed connection aforesaid.

23. In a refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, an evaporator wherein the condensed refrigerant is gasified in an atmosphere of the inert gas and mixed with the latter, a sealed connection between'the evaporator and a rotary multistage difiusion-filter receiving the mixed gases from evaporator, bearing means in said connection for the filter, a hermetically. sealed casing housing said filter and suitable rotating means, a collection chamber for the separated refrigerant gas in said casing having conduit connection with the peripheral portion of the filter, a condenser for the refrigerant gas, and means for separately returning the liquefied refrigerant and filtered inert gas to the evaporator.

24:. In a refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, an evaporator wherein the condensed refrigerant is gasified in an atmosphere of the inert gas and mixed with the latter, a connection between the evaporator and a rotary multiple-diffusion separator receiving the mixed gases from said evaporator, bearing means in such connection, said separator embodying a hollow hub with a concentric annular ring connected by perforate members with intervening filter elements and a suitable filler, a hermetically sealed casing housing the separator and rotating means therefor, a collection chamber for the separated refrigerant gas in said casing having conduit connection with the separator ring proportioned to balance flow of the separated refrigerant and inert gas, a condenser for the refrigerant gas, and means for separately returning the liquefied refrigerant and filtered inert gas to the evaporator.

25. In a refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, an evaporator wherein the condensed refrigerant is gasified in an atmosphere of the inert gas and mixed with the latter, a connection 'iger'ema the separated refrigerant gas, said casing having conduit connection with the separator annular ring proportioned to balance the flow of the separated refrigerant and inert gas, a condenser for the refrigerant gas, and means for separately returning the liquefied refrigerant and filtered inert gas to the evaporator.

26. In a refrigerating apparatus employing a refrigerant gas condensible at ordinary temperatures and an inert gas under pressure, an evaporator wherein the condensed refrigerant is gasified in an atmosphere of the inert gas and mixed with the latter, a connection between the evaporator and a rotary multiple -diflusion separator receiving the mixed gases from said evaporator, bearin means in. such connection, said separator em odying a spool-like hub with a concentric hollow ring connected by complementarily dished and central perforate members with intervening filter elements and a suitable filler, an imperforate casing about the separator, a hermetically sealed housing enclosing the separator and rotating means therefor, a collection chamber in said housing independent of the imperforate casing for the separated refrigerant gas, said casing having conduit connection with the separator hollow ring, a condenser for the refrigerant gas, means for separately returning the liquefied refrigerant and filtered inert gas to the evaporator, and valve means controlling refrigerant gas flow to the condenser and return of the separated inert gas to the evaporator whereby a proper balance of their respective flow is maintained.

27. A refrigerating apparatus as claimed in the immediately preceding claim wherein the means for returning the liquefied refrigerant from the condenser to the evaporator includes a retroverted pipe section forming a trap having a top aperture for uncondense gases, and a series of controlled apertures accommodating relief of excess gas.

In testimony whereof, I have hereunto signed my name at Philadelphia, Pennsylvania, this 21st day of March, 1931.

ARTHUR R. EARNSHAW. 

